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What’s new in laryngeal and hypopharyngeal cancers research and treatment?

Research into the causes, prevention, and treatment of laryngeal and hypopharyngeal cancers is now being done at many medical centers, university hospitals, and other institutions around the world.

Gene changes in laryngeal and hypopharyngeal cancers

A great deal of research is being done to learn how changes in certain genes cause cells in the larynx or hypopharynx to become cancerous.

The TP53 tumor suppressor gene is often altered in these cancers. Changes in this gene play a role in many head and neck cancers. Tests to detect TP53 gene changes may someday help find laryngeal and hypopharyngeal cancers early. These tests may also be used to better define surgical margins (check to see if all cancer cells have been removed) and to tell which tumors may respond better to surgery or radiation therapy. These tests are still experimental and are not used in the routine care of cancer patients at this time.

Changes in several other genes of have been found in cancers of the larynx or hypopharynx. These include the p16, NOTCH1, and cyclin D1 genes. Researchers hope this information might lead to better tests for early detection and to new targeted treatments.

Chemoprevention

Chemoprevention is the use of drugs to stop cancer from developing or from recurring once it has been treated.

Researchers are now trying to find out if certain drugs, vitamins, or other supplements can help prevent precancerous lesions from developing into cancers, but so far studies have not been successful.

In people whose cancer has been removed or destroyed with treatment, development of a second tumor in the head and neck area remains an important risk. Various drugs and supplements are being tested to see if they can reduce the risk of developing a new cancer. Retinoid analogs (chemicals related to vitamin A) have been studied for this purpose, but the results so far have been disappointing.

Treatment

Promising new forms of treatment are likely to make therapy more effective and less burdensome in the coming years.

Surgery and radiation therapy

Doctors continue to refine surgery techniques to try to limit the amount of normal tissue that is removed along with the tumor. This may help limit the side effects after treatment.

One new surgery technique now being studied for some early-stage cancers is transoral robotic surgery. In this approach, the surgeon operates by precisely moving robotic arms holding long surgical tools that are passed down the throat. This technique uses smaller incisions, so if it proves successful it might lessen the side effects from surgery. This approach is most commonly being used to treat pharyngeal tumors.

A newer approach to radiation therapy is proton beam therapy, which uses a beam of protons rather than x-rays to kill cancer cells. Unlike x-rays, which release energy both before and after they hit their target, protons cause little damage to tissues they pass through and then release their energy after traveling a certain distance. Doctors can use this property to, at least in theory, deliver more radiation to the tumor with less damage to nearby normal tissues. Proton beam therapy requires highly specialized equipment and is not widely available. Most doctors still consider its use to be experimental for laryngeal and hypopharyngeal cancers.

Chemotherapy and chemoradiotherapy

For advanced laryngeal and hypopharyngeal cancers, new chemotherapy delivery systems, such as direct injection into arteries feeding the cancer, are being tested in combination with radiation therapy in an attempt to improve how well they work. Newer chemotherapy drugs are also being tested.

Clinical trials are also studying ways to best combine chemotherapy drugs and to combine chemotherapy with radiation therapy. For example, studies are comparing chemotherapy given before, during, and/or after radiation therapy.

Targeted therapy

Newer targeted therapy drugs attack specific substances in or around cancer cells that help them grow. These drugs work differently from standard chemo drugs. They may work in some cases when chemo drugs don't, and they often have less severe side effects.

EGFR inhibitors: Squamous cell cancers of the larynx and hypopharynx (and other head and neck cancers) often have abnormally high levels of epidermal growth factor receptor (EGFR). Cetuximab (Erbitux), an antibody that blocks EGFR, is sometimes used to treat cancers of larynx and hypopharynx. Other EGFR blockers are under study for use in head and neck cancers, including panitumumab (Vectibix®), lapatinib (Tykerb®), and erlotinib (Tarceva®).

These drugs seem to work best when combined with other treatments, such as radiation and chemotherapy.

Angiogenesis inhibitors: Tumors need a large blood supply to grow, so they release chemicals that cause new blood vessels to form. Drugs that turn off these signals are called angiogenesis inhibitors. Drugs such as bevacizumab (Avastin®) and sunitinib (Sutent®) have helped treat other cancers, and are now being studied for treating head and neck cancers as well.

Photodynamic therapy

In this treatment, the patient is given a substance that makes the cancer cells more sensitive to light, and then the cancer is exposed to laser light a day later. This is being studied as a treatment for very early-stage laryngeal cancer.